The present invention relates to apparatuses and processes for detecting, analyzing, quantifying and sorting articles by material of construction. More particularly, the present invention relates to apparatuses and processes for detecting, analyzing, quantifying and sorting recyclable consumer articles comprising polymeric materials.
Polyester films, especially of polyethylene terephthalate (PET), are today widely employed in the manufacture of consumer articles, such as beverage bottles other food containers, because of their many advantages such as their mechanical properties, their transparency, their nontoxicity, their odorlessness and their tastelessness. However, their gas-barrier properties may limit their use in applications requiring a high protection of the bottled products against the action of external gases, in particular against the action of atmospheric oxygen or, conversely, may not allow the gas composition inside the bottles to be maintained constant.
In order to overcome this disadvantage, it is known to manufacture beverage bottles and other food containers from multilayer structures comprising a layer of PET and a layer of a barrier polymer.
Currently, there are no commercially available detection/analyzing/sorting technologies to differentiate bottles and flakes containing barrier polymers from the rest of the recyclable materials. It is important to detect and separate bottles or flakes containing barrier polymers in order to avoid problems in the end use applications of recycled articles that these barrier polymers may cause if they are in significant quantity, and to recover the barrier polymers for reuse. It is also important to analyze the quality of the feed stream to the recycling plant and that of the clean recycled articles produced by the recycling plant, in order to quantify the amount of barrier polymers.
It would be desirable to provide a process and apparatus that detects the presence of a barrier polymer in recyclable articles such as bottles and flakes. Such a system can be used to (1) sort out bottles containing barrier polymers from bottles that do not contain barrier polymers into one or more bins, (2) sort out flakes containing barrier polymers from flakes that do not contain barrier polymers into one or more bins, and (3) determine the amount of barrier polymers in the flakes or bottles.
It would also be desirable to make use of more than one kind of detector to allow quantification and sorting of multiple materials. For example, the detection systems of this invention can be used along with those for PVC detection systems as described in Provisional Patent Application Ser. No. 60/200,720, filed Apr. 27, 2000, incorporated herein by reference, to make use of the same system to sort out barrier and PVC articles out of recyclable bottles into one or more bins, sort out barrier and PVC flakes out of recyclable flakes into one or more bins, quantify barrier and PVC contamination in the flakes or bottles.